# physical sciences question

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#### athena21

##### Senior Member
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forgive me as I'm sure this question is easy for you guys, but please help me out.

What is the delay between transmission and reception of an FM broadcast sent on a carrier wave of frequency 90 MHz over a distance of 15 km?

A. 5 X 10(-8)
B. 2 X 10(-6)
C. 5 X 10(-5)
D. 2 X 10(4)

Obviously, I can eliminate D. But after that, please help as to how to do this problem and how to go about problems like these on the actual mcat.

thanks!

#### Diogenes

##### Succat
7+ Year Member
15+ Year Member
well, radio waves go 3 X 10^8 m/s, just like all emwaves/photons/light. So 15000 m / 300000000 m/s = 5 X 10^-5.

Is that right people?

#### Diogenes

##### Succat
7+ Year Member
15+ Year Member
The trick to this problem is not to get caught up in the unimportant details. EM waves (light, photons, whatever you like to call it) go the same speed no matter what the frequency. So the fact that they are FM waves at a certain frequncy is just thrown in there to trip you up if you don't know what you are doing.

#### Mudd

##### Charlatan & Trouble Maker
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Diogenes scores again!

You never miss any of these, do you?

#### Diogenes

##### Succat
7+ Year Member
15+ Year Member
Originally posted by Mudd
Diogenes scores again!

You never miss any of these, do you?

I must have missed a couple because I only bagged a 14 on PS.